Bone composite systems and related methods

Abstract

Provided herein are compositions comprising a bone composite and methods for treating bone defects, along with heating systems for processing the composite. The bone composite comprises about 35-50 wt.% bone component, about 10-30 wt.% polyethylene glycol, and about 30-40 wt.% PLGA (poly(dl-lactide-co-glycolide)) with a lactide-to-glycolide ratio between about 75:25 and about 85: 15, becoming moldable upon heating to between about the glass transition temperature and about the melting point (70-130 °C) of the polymer and setting into a rigid, resorbable implant upon cooling. Embodiments include variations in formulation and viscosity- and melt-controlling means. The disclosed heater provides a target heat load using direct contact, integrated, dual-chamber, or chemical heat source designs and is configured as a single-use device to maintain sterility. Intraoperative kits incorporating the composite, heater, and usage instructions are also described.

Description

BONE COMPOSITE SYSTEMS AND RELATED METHODSCROSS REFERENCE

[0001] This application claims the benefit of priority of the United States Provisional Patent Application Serial No. 63 / 710,471 filed on October 22, 2024, the disclosure of which is incorporated by reference in its entirety for all purposes.TECHNICAL FIELD

[0002] The present disclosure relates generally to a resorbable biomaterial composite. More specifically, the present disclosure relates to an allograft bio-composite configured to fill bone voids or gaps caused by trauma or surgery.BACKGROUND

[0003] Bones are a vital component of the human skeletal system, providing structure, support, and protection for the body's organs. Bones are composed mainly of collagen and calcium phosphate. While being one of the strongest and most dense organ systems, the bones of the skeletal system are prone to various deformities. Bone deformities are abnormalities in the shape, size, or structure of bones, often resulting from genetic factors, diseases, or injuries.

[0004] Bones are dynamic tissue structures that constantly undergo a process of remodeling to adapt to stress and repair injuries. However, not all deformities and injuries can be self-repaired by the bone during the remodeling phase, and injuries that can be self-repaired could take a substantial amount of time to heal, during which the bone may be unable to support loads.

[0005] Bone allografts are sometimes used to treat bone deformities comprising voids or gaps caused by trauma or surgery. The use of allografts involves the implantation of bone tissue from a donor into the recipient. The allograft technique is beneficial for patients with bone defects, fractures that are difficult to heal, or complex deformities because the allografts provide a scaffold that promotes new bone growth and healing, while also reducing the need for harvesting bone from a patient’s own body, which can minimize additional surgical trauma and complications.

[0006] However, the size and the shape of available allografts, as well as the need to maximize the mechanical strength and degradation rate, restrict the usage of allografts. Additionally, the variations in bone size and shape between the donor and the recipient also make traditional allografts a less optimal substitute material. Furthermore, the allografts cannot providerelatively immediate mechanical support, which may be needed during surgical procedures and the like.

[0007] Bone allograft composite grafts or scaffolds have also been used to treat bone deformities. Bone allograft composites can be malleable, allowing a surgeon to more easily manipulate and apply the allograft to a wide variety of bone defects and voids during implantation. Post-implantation, the allograft composites can provide a transient structure for advancing new bone tissue. Furthermore, the allograft composite degrades and is eventually replaced by the new bone tissue, and the degradation products of the allograft composite are eliminated from the body by the Krebs cycle and other processes.

[0008] Existing allograft composites are not optimized to maximize the amount of allograft tissue provided within the composite, thereby failing to maximize bone regeneration rates. Furthermore, the allograft tissue of existing allograft composites may only comprise cortical tissue, thereby utilizing only a partial amount of the allograft tissue available from each allograft tissue donation, while simultaneously adding to processing complexities. Furthermore, existing allograft composites may rely on non-resorbable materials or reusable heating systems to heat the composites before implantation, which require cleaning and sterilization after each use.

[0009] Accordingly, there exists a need for a substantially resorbable allograft bio-composite and a single-procedure-use heating system that addresses the foregoing technical problems.SUMMARY

[0010] The present disclosure provides a composite that comprises between about 35 wt.% to about 50 wt.% of a bone component, between about 10 wt.% to about 30 wt.% plasticizer comprising polyethylene glycol, and between about 30 wt.% to about 40 wt.% polymer comprising PLGA (poly(dl-lactide-co-glycolide)) having a ratio of lactide to glycolide of between about 75:25 and about 85: 15, wherein the composite becomes moldable upon heating between about the glass transition temperature and about the melting point of the polymer and, upon cooling, sets into a rigid, resorbable implant.

[0011] The present disclosure further provides a composite that comprises between about 35 wt.% to about 50 wt.% of a bone component, a viscosity-controlling means configured to reduce the composite’s viscosity when heated, and a melt temperature controlling means configured to transition the composite from a moldable state when heated to between about the glass transition temperature and about the melting point to a rigid, resorbable state upon cooling.

[0012] The present disclosure provides a method for treating a bone defect in a patient, which comprises heating a composite as disclosed herein to a temperature between about 70 °C and about 130 °C for between about 2 minutes and about 15 minutes or until the composite is uniformly heated, molding the heated composite to conform to the bone defect, and cooling the molded composite to a temperature below the glass transition temperature so that the composite sets into a rigid, resorbable implant.

[0013] The present disclosure provides a heater configured to provide a target heat load for heating a composite as disclosed herein to between about the glass transition temperature and about the melting point of the polymer, the heater comprising one or more embodiments selected from a direct-contact heating element, an integrated heating element including a reservoir for the composite with an operable plunger for extrusion, dual barrels with corresponding plungers for simultaneous dispensing, or a chemical heat source configured to produce an exothermic reaction upon exposure to air, and the heater is configured as a single-procedure-use device to support sterile and convenient handling of the composite.

[0014] The present disclosure provides an intraoperative kit that comprises a composite as disclosed herein, a heater as disclosed herein, and instructions for use.

[0015] Additional aspects, advantages, features, and objects of the present disclosure would be made apparent from the drawings and the detailed description of the illustrative aspects. It will be appreciated that features of the present disclosure are susceptible to being combined in various combinations without departing from the scope of the present disclosureBRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG. 1 shows a heater having a tray carrying a composite being slid into the heating chamber, representing the direct-contact heating embodiment.

[0017] FIG. 2 shows the heater of FIG. 1 fully assembled.

[0018] FIG. 3 shows an exploded view with a plunger positioned above a composite, before the composite is pushed into the heater.

[0019] FIG. 4 shows the heater of FIG. 3 with the heated composite after it has been pushed through and extruded from the heater.

[0020] FIG. 5 shows a top perspective view of a dual plunger and dual barrel system.

[0021] FIG. 6 shows a cross-sectional front plan view of the heater of FIG. 5, revealing the internal structure and distribution of heating elements within the dual-chamber configuration.Table 1 Reference Numerals 230 outlet port100 heater 300 dual plunger110 Housing 310 dual-barreled assembly120 Tray 312 first barrel125 Tab 314 second barrel130 chamber / reservoir 322 first shaft140 heating element 324 second shaft150 power source 326 dual handle160 sensor 328 first pad170 display 329 second pad180 control 700 composite220 plunger 750 heated composite226 handle F force228 PadDETAILED DESCRIPTION

[0022] The present disclosure provides a resorbable polymer composite osteoimplant bone void filler comprising human bone allograft (hereinafter, the “allograft bio-composite”) and a single-procedure-use (e.g., disposable) heating system configured to heat the allograft biocomposite such that the composite becomes malleable and can be implanted within the bone void defect. As discussed in greater detail herein, the allograft bio-composite comprises a composition of polymer, plasticizer, and allograft bone particles in a pre-determined ratio.

[0023] Specifically, the composite comprises between about 35 wt.% to about 50 wt.% of a bone component, between about 10 wt.% to about 30 wt.% plasticizer comprising polyethylene glycol, and between about 30 wt.% to about 40 wt.% polymer comprising PLGA (poly(dl-lactide-co-glycolide)) having a ratio of lactide to glycolide of between about 75:25 and about 85:15. The composite becomes moldable upon heating between about the glass transition temperature and about the melting point of the polymer and, upon cooling, sets into a rigid, resorbable implant.

[0024] As used herein, “composite” refers to an engineered material produced by combining two or more distinct components where a matrix holds the overall structure together and a reinforcement is selected to provide mechanical strength and other enhanced characteristics. In certain embodiments, the selected components include biodegradable polymers, natural bone allograft particles, or other materials combined to deliver improved strength, tailored elasticity,and controlled degradation. In certain embodiments, the composite is designed to mimic the structure and function of natural bone while providing flexibility in mechanical performance and biocompatibility for orthopedic applications such as implants and scaffolds.

[0025] As used herein, “resorbable” refers to a material that is gradually broken down and absorbed by the body after fulfilling a structural or therapeutic role. In certain embodiments, the resorbable material is manufactured from biocompatible polymers such as poly(lactic acid) (PLA), poly(glycolic acid) (PGA), poly(lactic-co-glycolic acid) (PLGA), polycaprolactone (PCL), poly-lactic-co-glycolic acid, poly L-lactic co-glycolide, and poly-para-dioxanone (PPD). In certain embodiments, the resorbable material is manufactured from resorbable ceramics, such as calcium phosphates. In certain embodiments, the resorbable material is designed for clinical applications, including fracture fixation devices, scaffolds for bone regeneration, supports for joint and ligament repair, and drug delivery matrices in orthopedic, dental, and cardiovascular fields. In certain embodiments, the resorbable material provides temporary stability and aids tissue healing as it is gradually replaced by native tissue through natural biological processes.

[0026] As used herein, “bone defect” refers to a missing or unhealed area of bone. In certain embodiments, the bone defect follows trauma, disease, congenital malformation, or surgical removal, sometimes resulting in structural discontinuity within the skeletal tissue.

[0027] As used herein, “bone void” refers to a contained space or cavity within bone where normal bone structure is absent. In some embodiments, the bone void results from infection, tumor resection, nonunion of fractures, osteonecrosis, or metabolic bone diseases. In certain embodiments, the bone void may compromise mechanical stability, support, and biological function.

[0028] As used herein, “bone component” refers to the natural organic and inorganic constituents incorporated into the composite. In certain embodiments, the bone component replicates the structure and function of human bone. In certain embodiments, the organic constituents of the bone component comprise one or more chosen from chitosan, collagen (type I), gelatin, glycosaminoglycans, proteoglycans, and silk fibroin. In certain embodiments, the inorganic constituents of the bone component comprise one or more chosen from bioglass, calcium phosphates, carbonate, fluoride, hydroxyapatite, magnesium, sodium, strontium, and zinc. In certain embodiments, the bone component comprises allograft bone, xenograft bone, autograft bone, cortical bone tissue, and / or cancellous bone tissue.

[0029] In certain embodiments, the composite comprises an allograft bone as the bone component. As used herein, “allograft bone” refers to bone tissue transplanted from a humandonor to a different recipient. In certain embodiments, the tissue is sourced from deceased individuals who have authorized donation. In certain embodiments, the tissue is processed to ensure safety before implantation. In these embodiments, donors are screened and medically cleared by appropriate Medical Directors, or authorized designates, to ensure they meet donor eligibility requirements for implantation within their respective geographies (United States and / or International). In certain embodiments, allograft bone is available fresh, frozen, freeze-dried, mineralized, and / or demineralized. In certain embodiments, allograft bone is employed in orthopedic, spinal, dental, and reconstructive surgeries to repair or replace damaged bone, serve as a scaffold for new bone growth, and / or enhance structural support. In certain embodiments, allograft bone acts primarily through osteoconduction by providing a natural framework for recipient bone cells to grow into. In certain embodiments, allograft bone reduces the need for harvesting bone from the recipient.

[0030] As used herein, “xenograft bone” refers to bone graft material derived from a different species than the patient. In certain embodiments, the patient is human and the xenograft bone is sourced from cows or pigs. In certain embodiments, xenograft bone is processed to remove organic components and reduce immunogenicity. In certain embodiments, xenograft bone is a scaffold that aids new bone growth during dental, spinal, and reconstructive procedures.

[0031] As used herein, “autograft bone” refers to bone tissue transplanted from one location to another within the same individual. In certain embodiments, autograft bone is harvested from the iliac crest. In certain embodiments, autograft bone is osteogenic, osteoinductive, and / or osteoconductive with high integration rates as it contains the individual’s own living cells.

[0032] In certain embodiments, the bone component comprises both cortical and cancellous bone tissue. As used herein, “cortical bone tissue” refers to the dense, compact outer layer of bone. In certain embodiments, cortical bone tissue provides strength, rigidity, and protection. In certain embodiments, cortical bone tissue provides mechanical support and load-bearing functions in grafting and reconstruction.

[0033] As used herein, “cancellous bone tissue” refers to the porous, inner structure of bone. In certain embodiments, cancellous bone tissue comprises a lattice-like network. In certain embodiments, cancellous bone tissue provides a large surface area for bone marrow, cellular activity, and vascularization. In certain embodiments, cancellous bone tissue is used in grafts to promote rapid healing and integration due to its high osteoconductivity.

[0034] Among other things, the present disclosure focuses on the handling characteristics of the composite. Precise formulations are disclosed with defined viscosity and softening parameters that enable the composite to reliably transition to a moldable state at a specifiedtemperature range and then set into a stable, shape-retaining implant. As used herein, “moldable” refers to measurable handling properties, ensuring that the material achieves the proper softness for shaping and holds its configuration during surgical implantation.

[0035] The allograft bio-composite of the present disclosure comprises a higher proportion of bone allograft tissue, and unique tissue mix, when compared with prior formulations to enhance bone regeneration and healing. Specifically, the allograft bio-composite of the present disclosure maximizes the amount of human bone tissue while balancing the handling characteristics of the graft for implantation. An increased overall allograft ratio augments contact between allograft particles and apposition to host bones, thereby offering a continuous bioactive phase when implanted. Essentially, without wishing to be bound by theory, the densely packed bone particles of the allograft bio-composite create a continuous pathway for bone cells to infiltrate within the graft. This feature is conducive to the remodeling process mediated by the osteoclasts and osteoblasts and improves the efficacy of the disclosed allograft bio-composite.

[0036] The present disclosure provides an allograft bio-composite having bone allograft tissue in pre-determined ratios to heal bone deformities and defects.

[0037] The present disclosure also provides a single-procedure-use heating system to heat the allograft bio-composite to make it formable prior to implantation.

[0038] The present disclosure also reduces processing complexities and maximizes the use of donated allograft tissue of the allograft bio-composite by providing a mix of cortical bone tissue and cancellous bone tissue particles and / or bone fibers.

[0039] The present disclosure also improves handling characteristics of the allograft biocomposite by selecting suitable polymer and plasticizer components, which result in improved moldability of the allograft bio-composite.

[0040] The present disclosure also increases the efficacy of the allograft bio-composite by maximizing the cortical bone tissue and cancellous bone tissue to provide a continuous osteoconductive pathway for the bone to regenerate.

[0041] In one aspect of the present disclosure, the allograft bio-composite comprises a composition of polymer component, plasticizer component, and an allograft component in a pre-determined ratio. The polymer used in the aforementioned composition can be Poly dl-lactide-co-glycolide 85:15 (“PLGA”), and the plasticizer used in the aforementioned composition can be Polyethylene glycol 8000 (“PEG”). The allograft used in the aforementioned composition can be a combination of cortical bone tissue and cancellous bone tissue. This combination of cortical bone tissue and cancellous bone tissue honors the gift ofhuman tissue donation by optimizing the amount of the donor tissue that can be used in the allograft bio-composite. This combination of cortical bone tissue and cancellous bone tissue improves the manufacturing of the allograft biocomposite as it maximizes tissue utilization, reduces scrap, and / or increases the yield of osteoimplant. This maximizes the gift of human tissue donation and also provides ease of tissue sourcing and processing.

[0042] The present disclosure substantially addresses the aforementioned known problems by providing an implant that can seamlessly integrate with the host bone tissue, support cellular activity, and stimulate the regeneration of bone in a manner that is both controlled and predictable.

[0043] The polymer used in the aforementioned composition can be poly dl-lactide-co-glycolide (“PLGA”), and the plasticizer used in the aforementioned composition can be polyethylene glycol (“PEG”). Notably, the allograft particles used in the aforementioned composition are a combination of both cortical bone tissue and cancellous bone tissue.

[0044] As used herein, “poly dl-lactide-co-glycolide” or “PLGA” refers to a synthetic, biodegradable, and biocompatible copolymer comprising of poly L-lactide co-glycolide monomers joined by ester bonds. In certain embodiments, PLGA is amorphous and transparent when dl-lactic acid is present, with a melt temperature of about 130 °C. In certain embodiments, PLGA degrades at an adjustable rate tuned by the ratio of lactide to glycolide, wherein a higher glycolide content is associated with a faster degradation rate, while PLGA of different molecular weights and monomer ratios is tailored for a range of clinical applications.

[0045] The thermal characteristics of PLGA make it suitable for use in the allograft biocomposite. As those of skill in the art will understand, the thermodynamic behavior of a polymer is defined by its glass transition temperature (“Tg”), which refers to the temperature at which an amorphous polymer or the amorphous regions of a semi-crystalline polymer in certain embodiments undergo a reversible change from a rigid, glassy state to a soft, rubbery state as molecular mobility increases with heat. In certain embodiments, this temperature establishes the operating range for mechanical properties such as flexibility and strength in polymers and bio-composites. The Tg of the polymer dictates the handling properties and malleability of the allograft bio-composite when heated to the requisite temperature in the heating system.

[0046] As used herein, “plasticizer” refers to a substance added to polymeric or composite materials to increase flexibility, decrease brittleness, and / or enhance workability during processing. In certain embodiments, plasticizers are chosen from water, glycerol, polyethyleneglycol, citrate esters, sorbitol, or propylene glycol, and are selected based on compatibility with the matrix and intended biomedical use.

[0047] In certain embodiments, the plasticizer ranges between about 10 wt.% to about 30 wt.% of the total formulation, such as between about 10 wt.% and about 15 wt.%, between about 15 wt.% and about 20 wt.%, between about 20 wt.% and about 25 wt.%, between about 25 wt.% and about 30 wt.%, or up to about 30 wt.%. Moreover, in certain embodiments, the plasticizer is maintained at least about 10 wt.% and not more than about 30 wt.%.

[0048] In certain embodiments, the plasticizer is polyethylene glycol. As used herein, “polyethylene glycol” or “PEG” refers to a synthetic, hydrophilic polyether of repeating ethylene oxide units used for its solubility, biocompatibility, and low immunogenicity in composite materials. Suitable examples are polyethylene glycol 1000 (PEG 1000), polyethylene glycol 2000 (PEG 2000), polyethylene glycol 3350 (PEG 3350), polyethylene glycol 4000 (PEG 4000), polyethylene glycol 6000 (PEG 6000), polyethylene glycol 8000 (PEG 8000), and polyethylene glycol 20000 (PEG 20000). In some embodiments, the plasticizer is PEG 8000.

[0049] In certain embodiments, the polymer ranges between about 30 wt.% to about 40 wt.% of the total formulation, between about 30 wt.% and about 35 wt.%; or between about 35 wt.% and about 40 wt.% Moreover, in certain embodiments, the polymer is maintained at least about 10 wt.% and not more than about 40 wt.%.

[0050] In certain embodiments, the composite is heated between about 70 °C and about 130 °C, . In certain embodiments, the composite is heated for between about 2 minutes and about 15 minutes or until the composite reaches a uniform temperature before surgical implantation.

[0051] The melting point of a polymer dictates the upper range of temperature of the polymer beyond which the polymer becomes flowable, and the crystalline domain mobilizes. During production of the allograft bio-composite, this is the temperature that is leveraged for processing the polymer and mixing it with the bone allograft particulates to make the allograft bio-composite.

[0052] The melting point (“Tm”) for PLGA is about 140°C. Furthermore, PLGA is a biodegradable polymer that degrades through a process of hydrolytic degradation and chain scission. When exposed to water, PLGA initiates a hydrolytic degradation process, breaking down into its constituent components, lactic acid and glycolic acid, which are subsequently metabolized and eliminated from the body.

[0053] According to some aspects of the present disclosure, polyethylene glycol (“PEG”) 8000 can be used as the plasticizer in the allograft bio-composite, because PEG is a water-solubleand bio-eliminable polymer. With regard to PEG 8000, this specific formulation has hydrophilic properties that allow it to absorb water, creating a hydrated environment conducive to cell adhesion and proliferation. Furthermore, PEG 8000 exhibits minimal cytotoxicity and immunogenicity, making it particularly suitable for biological applications. Additionally, PEG is generally regarded as safe and non-toxic and can be eliminated easily from the body. The molecular weight of PEG 8000 influences its elimination rate. For example, higher molecular weight PEGs are eliminated more slowly than lower molecular weight ones. Beneficially, PEG 8000 has a plasticizing effect, which effectively lowers the Tg of a polymer, such as biodegradable PLGA. This provides malleability to the allograft bio-composite scaffold during shaping and molding prior to and during implantation.

[0054] In certain embodiments, a composite comprises between about 35 wt.% to about 50 wt.% of a bone component, a viscosity-controlling means configured to reduce the composite’s viscosity when heated, and a melt temperature controlling means configured to transition the composite from a moldable state when heated to between about the glass transition temperature and about the melting point to a rigid, resorbable state upon cooling.

[0055] As used herein, “viscosity-controlling means” refers to components that regulate or adjust the thickness, flow, and processability of a composite during manufacturing or application. Suitable examples include, but are not limited to, cellulose derivatives, such as methylcellulose and carboxymethylcellulose sodium, low-viscosity monomers, such as triethylene glycol dimethacrylate (TEGDMA), glycerol, polyethylene glycol (PEG), propylene glycol, poly caprolactone, and fumed silica. In certain embodiments, each viscosity-controlling means is selected for its ability to increase or decrease viscosity to achieve desired handling and mechanical properties. In certain embodiments, the composite comprising the viscositycontrolling means comprises an allograft bone as the bone component. In certain embodiments, the composite comprising the viscosity-controlling means comprises a bone component that comprises both cortical and cancellous bone tissue.

[0056] As used herein, “melt temperature controlling means” refer to components or strategies to modify, stabilize, or tailor the temperature at which a composite transitions from solid to flowable melt during processing. Suitable examples of melt temperature controlling means include, but are not limited to, polymer blend ratios, additives such as polyethylene glycol, plasticizers, nucleating agents such as carbon nanotubes, inorganic fillers including calcium phosphates or silica, and copolymers designed to lower or raise the melt temperature by altering crystallinity or molecular interactions.

[0057] In certain embodiments, a method for treating a bone defect comprises heating a composite to a temperature between about 70 °C and about 130 °C for between about 2 minutes and about 15 minutes, such as about 10 minutes, or until the composite is uniformly heated, molding the heated composite to conform to the bone defect, and cooling the molded composite to a temperature below the glass transition temperature such that the composite sets into a rigid, resorbable implant. In certain embodiments, the bone defect comprises a bone void. In certain embodiments, the method further comprises shaping the heated composite using a mold that defines a predetermined implant geometry. In certain embodiments, the method further comprises performing the cooling step by applying a cold lavage fluid to rapidly lower the composite’s temperature.

[0058] Provided herein are heaters configured to provide a target heat load for heating the composite to between about the glass transition temperature and about the melting point of the polymer. Referring to FIGS. 1 & 2, a heater 100 comprises a housing 110 with a chamber 130 having a heating element 140, a power source 150, a display 170, and a control 180. The composite 700 is loaded onto a tray 120. While holding tab 125, the tray 120 is inserted into chamber 130 under force F to heat the composite to the target temperature.

[0059] As used herein, “target heat load” refers to a predetermined amount of thermal energy applied to the composite to raise its temperature to between about the glass transition temperature and about the melting point and render the composite uniformly moldable for processing into a rigid, resorbable implant upon cooling.

[0060] As used herein, “single-procedure-use device” refers to a product designed and labeled by manufacturers for a single patient-use or procedure, typically based on material choices and lack of validated reprocessing protocols. Such labeling, however, does not inherently prohibit their reuse, as certain single-procedure-use devices may be safely and effectively reprocessed and reused if validated cleaning, sterilization, and testing are performed to ensure the device remains functional and safe.

[0061] The term “patient” is generally synonymous with the term “subject” and includes any animal having bones, which includes all mammals and humans. Examples of patients include humans, livestock such as cows, goats, sheep, pigs, and rabbits, and companion animals such as dogs, cats, rabbits, and horses. In certain embodiments, the patient is a human.

[0062] As used herein, “sterile handling” refers to production processes and packaging methods that protect the device from contamination, enable straightforward transfer into a sterile environment, and maintain sterility during storage and before use. In certain embodiments, pre-sterilized single-procedure-use heaters are packaged in heat-sealed orpeelable sterile pouches, thereby allowing direct aseptic transfer to the composite setup, and supporting compatibility with conventional sterilization techniques, such as dry heat, E-beam, gamma irradiation, or ethylene oxide to guarantee freedom from pathogens.

[0063] As used herein, “convenient handling” refers to features or packaging of a device that simplify logistics, setup, and / or use. These features include, but are not limited to, ergonomic form factors, color-coded activation, integrated connectors, or single-step deployment, all aimed at reducing operational burden, streamlining workflow, and supporting efficient use.

[0064] In certain embodiments, the heater comprises a direct-contact heating element. As used herein, “direct-contact heating element” refers to a component integrated into or placed near a composite structure that provided heat directly through physical contact with the material. In certain embodiments, the direct-contact heating element allows efficient, uniform, and rapid temperature control during processing, curing, or shaping. In certain embodiments, direct-contact heating elements include embedded resistive wires or metal films, carbon fiber structures, flexible silicone heater mats, or heating fabrics that deliver heat via electrical resistance or induction, enabling precise control of local temperatures for composite molding, repair, and manufacturing applications. These elements improve heating efficiency, energy usage, and product quality by reducing reliance on indirect heating methods such as ovens or autoclaves. In certain embodiments, the heater comprises a housing adapted to receive the composite, a tray configured to be slid into the housing, and one or more direct-contact heating elements arranged to transfer heat by conduction to the composite.

[0065] In certain embodiments, the heater comprises an integrated heating element. As used herein, “integrated heating element” refers to a heating component embedded within or directly incorporated into composite materials, molds, or structures to enable precise, uniform, and adjustable thermal control during fabrication, curing, or operational processes. In certain embodiments, these elements comprise resistive heating films, knitted heating fabrics, thin metallic wires, and / or carbon fiber layers positioned as part of the composite’s internal layup and connected to electrical power sources. In certain embodiments, the integrated heating element provides localized or distributed heating while improving laminate quality, reducing void content, and streamlining composite manufacturing by eliminating the need for external ovens or autoclaves.

[0066] Referring to FIGS. 3 & 4, a heater 100 having a housing 110 comprising a reservoir 130 for containing the composite 700, a plunger 220 operable to extrude the heated composite 750 through an outlet port 230. Integrated heating elements 140 are disposed on the reservoir walls to maintain the composite 700 at the target temperature. Plunger 220 comprises a handle 226and a pad 228 for pushing the composite 700 under force F into the reservoir 130, through outlet port 230, and onto tray 120, which may also have a heating element 140.

[0067] In certain embodiments, the heater comprises a chemical heat source positioned adjacent to a composite unit and configured to produce an exothermic reaction upon exposure to air to generate the target heat load required to heat the composite. As used herein, “chemical heat source” refers to an exothermic composition that generates heat through controlled chemical reactions, allowing in situ thermal processing without external ovens or electrical heating elements. Suitable examples include, but are not limited to, magnesium-iron or magnesium-salt reaction mixtures (activated by water to release heat), calcium oxide-based formulations (quicklime and water, commonly used in self-heating packs), and commercial exothermic epoxy formulations where dual-component resin and hardener systems release heat during the curing process. Other examples include iron-oxidation “heat pack” compositions, sodium acetate trihydrate supersaturation systems, and self-heating compositions based on thermite or metal powder oxidizers (used in industrial but less common for medical applications).

[0068] Referring to FIGS. 5 & 6, a heater 100 is configured as a single-procedure-use device for receiving the composite 700 and supporting sterile and convenient handling of the composite 700 once heated. In this embodiment, heater 100 is configured as a dual-barreled assembly 310, comprising a first barrel 312 having a heating element 140, a second barrel 314 having a heating element 140, and a corresponding dual plunger 300. Dual plunger 300 comprises a dual handle 326 connected to first shaft 322 having first pad 328 and to second shaft 324 having second pad 329. First shaft 322 is configured to insert into first barrel 312, and second shaft 324 is configured to insert into second barrel 314. As such, dual-barreled assembly 310 is configured to simultaneously dispense heated portions of the composite 700 through outlet port 230 for mixing or joint delivery to a bone defect.

[0069] In certain embodiments, an intraoperative kit comprises the composite, the heater, and instructions for use.

[0070] In certain embodiments, the method for treating a bone defect comprises heating the composite by employing a heater integrated into the intraoperative kit.EXAMPLESExample 1 - Bone composites

[0071] Exemplary formulations and acceptable ratios of the polymer, plasticizer, and allograft bone particle components of the allograft bio-composite are listed in Table 2, below:Table 2Formulation Allograft Particle Size (wt.%) Plasticizer Polymer (PEG 8000 wt.%) (PLGA, wt.%) A 50% (800-300 pm) 20% 30%B 50% (2 mm-500 pm) 20% 30%C 45% (800-300 pm) 20% 35%D 45% (2 mm-500 pm) 20% 35%E Partial Demin 50% (2 mm-500 pm) 20% 30%F 40% (2 mm - 300 pm) 25% 35%G 30% (2 mm - 300 pm) 30% 40%H 50% (2 mm - 300 pm) 10% 40%I 50% (2 mm - 300 pm) 15% 35%

[0072] Table 2 comprises exemplary formulations A-G having various acceptable ratios of the polymer, plasticizer, and allograft bone particle components of the allograft bio-composite. In some embodiments, unlike prior allograft bio-composites, the allograft bio-composites of the present disclosure do not comprise a porogen component.

[0073] As used herein, “porogen” or “pore-forming agent” refers to a material intentionally added to a composite or scaffold to generate controlled porosity upon its removal. In certain embodiments, the pores are formed through dissolution, leaching, and / or thermal decomposition of the porogen. In certain embodiments, the void structure created by removal of the porogen is configured to support cellular ingrowth, nutrient exchange, and / or tissue integration. Suitable examples of porogens include, but are not limited to, biochar, salt (such as ammonium chloride, calcium chloride, potassium chloride, and sodium chloride), starch (such as com starch, potato starch, rice starch, sago starch, and wheat starch), sugar (dextran, fructose, glucose, lactose, sucrose, and trehalose), and calcium lactate.

[0074] Advantageously, elimination of the porogen component allows for optimization of the component ratios of the polymers (e.g., PEG 8000 and PLGA 85 / 15) and human tissue allograft components of the allograft bio-composite. For example, as described in greater detail below, by eliminating the porogen component, the relative percentage weights of one or more of the allograft components, the plasticizer component, and the polymer components can be increased or tailored to achieve particular desired characteristics of a given allograft bio-composite formulation.

[0075] Another advantage of the aforementioned blend of cortical and cancellous tissues over known allograft bio-composite formulations comprising only cortical tissue is that it maximizes the gift of human tissue donation, enhances ease of manufacturability, and reduces supply chain complexities related to sourcing pure cortical allograft tissue, or one tissue type. For example, the use of both cortical and cancellous tissues improves manufacturing processes because it reduces scrap, increases yield, and helps more patients. Notably, known allograft composites may not make use of both cortical and cancellous tissues because it was previously thought that cortical tissue was superior to cancellous tissue. However, increasing the overall proportion of human allograft tissue up to 50% can have a greater impact on bone regeneration and healing, as compared to formulations having a lesser amount of allograft tissue. Combined cortical and cancellous human tissue is also easier to attain, as compared to cortical human tissue separately.

[0076] Furthermore, the increased total allograft component ratio over known allograft biocomposite formulations augments the contact between allograft particles and apposition to host bones, thereby providing a continuous bioactive phase when implanted within the bone void.

[0077] The preferred ratio of the cortical bone tissue and cancellous bone tissue in the allograft component is in the range of 50-80% cortical bone tissue and 20-50% cancellous bone tissue.. An overall range between 0-100% by weight of cortical bone tissue and cancellous bone tissue is also acceptable according to some aspects of the present disclosure.

[0078] Advantageously, an increased polymer component proportion in the allograft biocomposite enhances its moldability, thereby improving handling and enabling a surgeon to shape the osteoimplant graft more effectively based on the requirements of a given application. The size of the allograft particles and their surface characteristics can influence the osteoimplant graft’s efficacy by modifying the rate of remodeling and its handling characteristics.

[0079] According to some aspects of the present disclosure, the allograft bio-composite comprises a polymer phase configured to be resorbed within 6 to 12 months following implantation. According to other aspects of the present disclosure, the allograft bio-composite comprises a polymer phase configured to be resorbed within 6 months following implantation.

[0080] Advantageously, the polymer and plasticizer in the allograft bio-composite provides a setting time for the osteoimplant, which is less than or equal to 10 minutes.

[0081] As noted above, the allograft bio-composite formulations described herein reduce the cost of production, improve handling time and efforts, and increases efficacy. For example, the cost of producing the disclosed allograft bio-composite is reduced by providing a mix ofcortical bone tissue and cancellous bone tissue particles based, for example, on a limited supply of isolated cortical tissue and market demand trends driving cost. The handling of the allograft bio-composite is improved by using PEG 8000 as the plasticizer component and PLGA as the polymer component, which results in improved moldability of the allograft bio-composite. Moreover, the efficacy of the allograft bio-composite is increased by maximizing the cortical bone tissue and cancellous bone tissue and providing a continuous osteoconductive pathway for the bone to regenerate. This combination of cortical bone tissue and cancellous bone tissue in the allograft tissue honors the gift of human tissue donation by optimizing the amount of the donor tissue that can be used in the allograft bio-composite. This combination of cortical bone tissue and cancellous bone tissue improves the manufacturing efficiencies of the allograft biocomposite as it reduces scrap and increases the yield of each human tissue donation, from which the allograft particles are derived, thereby maximizing the gift of human tissue donation and also providing ease of tissue sourcing and processing.Example 2 - Methods for producing bone composites

[0082] The present disclosure also provides methods for producing the allograft bio-composite described hereinabove. First, an allograft bio-composite formulation (e.g., from Table 2) is selected based on the formulation’s particular characteristics and their applicability to a given application. Next, the polymer component, the plasticizer component, and the allograft component of the selected formulation are prepared (e.g., weighed or measured) based on the ratios described in Table 2. The polymer component, the plasticizer component, and the allograft component of the selected formulation are then introduced into a mixing device configured to heat the components to a temperature between the glass transition temperature (Tg) and the melting point (Tm) of the PLGA, preferably from 130 °C-165 °C, and further configured to provide mechanical agitation of the components, thereby providing sufficiently low viscosity of the polymer component and the plasticizer component (e.g., due to heating the components to a temperature between Tg and Tm) to thoroughly mix the components, while avoiding tissue / polymer damage due to excessive temperatures. According to some aspects of the present disclosure, the mixing device can be a torque rheometer (e.g., a Brabender-type mixer). After mixing, the allograft bio-composite is removed from the mixing device and allowed to cool. The composite is separated into individual units for packaging.

[0083] After the allograft bio-composite units have cooled to a temperature below Tg (e.g., solidified), they are wrapped and packaged. Wrapping and packaging can comprise wrapping each of the allograft bio-composite units in one or more foils and sealing the same. Lastly,wrapped and packaged allograft bio-composite units are sterilized using a terminal sterilization dose of gamma radiation up to 35 kilogray (kGy) and preferably between 25 kGy and 35 kGy. According to some aspects of the present disclosure, the terminal sterilization dose can be determined based on the bioburden (e.g., contamination) picked up from the incoming raw materials and during production. According to further aspects of the present disclosure, the gamma radiation dose is determined based on a bioburden assessment and a dosing study to ensure a given sterilization assurance level is satisfied.

[0084] The present disclosure also provides methods for utilizing the allograft bio-composite described hereinabove to create a scaffold within a bone defect (e.g., void) to stimulate regeneration and healing of the bone.

[0085] First, the allograft bio-composite is heated by the heating system for about ten (10) minutes, or until the allograft bio-composite reaches an internal uniform temperature of between 70 °C-130 °C (e.g., above Tg but below Tm). This is to avoid allograft and polymer damage while enabling the allograft bio-composite to become malleable for implantation. According to some aspects of the present disclosure, the heating system can be a single-procedure-use (e.g., disposable) heating system used to heat the allograft bio-composite.Example 3 - Heaters

[0086] For example, the heating system can comprise a single-procedure-use electrical or chemical heat source packaged adjacent a single unit of the allograft bio-composite (e.g., in a taco-style configuration). In one such configuration, the heat source can be a single-procedure-use chemical component comprising, but not limited to, iron powder, activated carbon, vermiculite, cellulose, and salt. When exposed to air, the iron in the aforementioned composition oxidizes, thereby producing an exothermic reaction.

[0087] Additional single-procedure-use heating systems of the present disclosure include one or more electrical heating elements (e.g., PCBs) sandwiching the allograft bio-composite, a temperature-controlled water bath, or an infrared heating device. Notably, the single-use disposable heating system of the present disclosure provides a significant improvement over known reusable heating systems by eliminating the need for cleaning and sterilizing the heating system after each use, thereby eliminating the possibility of infections and other complications due to contamination of the heating system. Those of ordinary skill in the art will understand other known, or later developed, single-procedure-use heating systems can be utilized to heat the allograft bio-composite without departing from the spirit and scope of the present disclosure.

[0088] Various housings can be used with the heaters disclosed herein. In some embodiments, the housing comprises a tray, where a composite is placed on a tray that slides into a chamber having one or more integrated heating elements. In some embodiments, the housing comprises a cartridge or sleeve. In such embodiments, the heater is a pre-sterilized, single-procedure-use device that combines heating elements and the composite in one compact, enclosed unit, often featuring mechanisms such as pull-tabs for sterile technique extraction. In some embodiments, the housing comprises enclosures with integrated insulation and extraction features. In such embodiments, the housing is configured to contain the composite and heating element and provides features (e.g., a pull-tab mechanism) to aid removal without compromising sterility. In some embodiments, the housing comprises two chambers. In such embodiments, the housing comprises dual barrels or sections to work with dual plunger systems for simultaneous or controlled dispensing of a heated composite. In some embodiments, the heater comprises reservoir or cartridge-like housings that combine a temperature-controlled environment with an integrated dispensing mechanism (e.g., via a plunger, piston, or screw-driven extruder).

[0089] Various heating elements can be used in the heaters disclosed herein. In some embodiments, the heating element is a direct-contact element, such as resistive metal strips, plates, or flexible foil heaters that physically contact the composite to transfer heat by conduction. In some embodiments, the heating element is a cartridge-style integrated element embedded in a sleeve or cartridge configuration that wraps around the composite. In some embodiments, the heating element is an exothermic chemical heat source, such as a single-procedure-use chemical composition (e.g., a mixture comprising iron powder, activated carbon, vermiculite, cellulose, and salt) that generates heat upon exposure to air. In some embodiments, the heating element is an electrical heating element, for example, those formed on printed circuit boards (PCBs) or other resistive electrical constructs that might sandwich the composite material. In some embodiments, the heating element is a temperature-controlled bath, such as a water bath that maintains heat through circulating or static water heated to the desired temperature range. In some embodiments, the heating element is an infrared device that emits radiant energy onto the composite without direct contact. In some embodiments, the heating element is a heated reservoir wall, for example, in an extrusion-based design that continuously keeps a stored quantity of composite at the working temperature during a dispensing operation.

[0090] After heating, the allograft bio-composite becomes malleable and can be implanted within (e.g., grafted to) a bone defect to stimulate regeneration and healing of the bone. The allograft bio-composite can be lavaged with cold water to reduce the temperature of the allograft bio-composite below Tg, thereby setting the allograft bio-composite within the bonedefect. Lastly, the bio-composite may be machined (i.e. drilled, remed, or set with a screw or similar surgical hardware to further secure the bone). Those of ordinary skill in the art will understand, the allograft bio-composites disclosed herein are configured to fill bony voids and gaps of the extremities, spine, oral maxillofacial, foot and ankle, and pelvis that are caused by trauma or surgery, and are not intrinsic to the stability of the bony structure.

[0091] Additional formulations and experimental designs related to the allograft bio-composite of the present disclosure are referred to in connection with Tables 2-6. Specifically, as shown in Table 3, five (5) exemplary formulations, two (2) exemplary gamma doses for sterilization, and two (2) ratios of cortical / cancellous tissues for the allograft component of each of the formulations are provided, with two samples from each formulation being prepared and tested, which together total forty (40) samples.Table 3Number of Formulations (A, B, C, D, E) 5Number of Gamma Doses (25 kGy, 35 kGy) 2Number of Tissue Cortical / Cancellous Ratios 2Number of samples per formulation for handling 2Number of Samples 40Volume per sample (g) 10Total sample volume (g) 400

[0092] Specifications for the mixing device and processing times for the plasticizer, polymer, and allograft are provided in Table 4, below.Table 4Mixer Capacity (cc) 60Number of Mixer Runs 7Time Per Run (hour) 4Total Time of Runs (hours) 27

[0093] Raw material volumes for the plasticizer, polymer, and allograft according to one formulation of the allograft bio-composite of the present disclosure are listed in Table 5, below.Table 5Components of the allograft Percentage Needed Safety Order bio-composite volume AmountPlasticizer (PEG) in grams (g) 20% 80 2 160 Polymer (PLGA) in grams (g) 35% 140 2 280 Allograft small in grams (g) 50% 100 2 200 Allograft large in grams (g) 50% 100 2 200

[0094] Additional formulations of the allograft bio-composite of the present disclosure, having cortical / cancellous tissue ratio of 50 / 50% in the allograft by weight, a total allograft composition between 45-50%, and varying particle sizes are listed in Table 6, below.Table 6Formulation Allograft Particle Size PEG PLGA Sample #A 50% Small 20% 30% 2B 50% Large 20% 30% 2C 45% Small 20% 35% 2D 45% Large 20% 35% 2E 50% Large 20% 30% 2

[0095] Additional formulations of the allograft bio-composite of the present disclosure, having a cortical / cancellous tissue ratio of 70 / 30% in the allograft by weight, total allograft composition between 45-50%, and varying particle sizes are listed in Table 7, below.Table 7Formulation Allograft Particle Size PEG PLGA Sample #A 50% Small 20% 30% 2B 50% Large 20% 30% 2C 45% Small 20% 35% 2D 45% Large 20% 35% 2E 50% Large 20% 30% 2

[0096] Experiments were conducted according to a predefined experimental design for Formulations A-D (Table 2). All experimental findings were recorded in a laboratory notebook and documented in development trial protocols that described the processing steps of cleaning,weighing components, mixing, final packaging of the composite material, and terminal irradiation.

[0097] In addition to these formulations, PLGA from three different suppliers was evaluated for target handling and resorption characteristics. The desired PLGA specifications were a ratio of 79-85 mol% lactide to 15-21 mol% glycolide, an intrinsic viscosity (before sterilization) in the target range of about 1.4- 1.7 dL / g, with an expected reduction post-sterilization to about 0.7 dL / g, ester termination, an amorphous structure, a white to off-white color, and a granular form.

[0098] The first PLGA polymer used was supplied by a Chinese manufacturer under the designation “Alpha.” Alpha PLGA 85:15 was characterized by an intrinsic viscosity of about 1.5 dL / g, a molar ratio near 84.8, a molecular weight of about 180,000 Da, and a numberaverage molecular weight around 90,000 Da (PDI -1.99). When Formulations A-D were prepared with Alpha PLGA at a 50 / 50 cortical / cancellous bone ratio, the resulting prototypes did not mix properly and were brittle. In addition, Alpha PLGA had to be heated to about 160 °C to melt — well above the expected processing setpoint of about 130 °C — suggesting issues such as cross-linking, impurities, or excessively high viscosity.

[0099] The samples were subsequently packaged using an iron heater operating in a high-temperature range to complete packaging before sterilization. Before heating, the formulations were brittle and granola-like; after heating, they became thin (about 1-3 mm) and flexible, with significantly improved texture and handling. Visual evaluation confirmed that all formulations met the target bone content of about 45-50 wt.%. Based on these observations, the effect of varying the bone particle ratios was further investigated to bracket acceptable particle size ranges (e.g., evaluating 70 / 30 cortical-to-cancellous, 100% cortical, and 100% cancellous bone). Later, a handling test was performed on post-sterile units using a standardized procedure.

[0100] A thermocouple confirmed that the product heater achieved about 110 °C. A sample was inserted into the heater to monitor the time for reaching the desired temperature. After about 2-3 minutes, the temperature increase slowed to around 92 °C upon removal and evaluation, no samples were workable. Consequently, a new PLGA supplier was sought.

[0101] Three samples of PLGA were obtained from Corbion N.V. (Amsterdam, the Netherlands), designated as PURASORB™ PLG 8531, PLG 8523, and PLG 8218. PURASORB™ PLG 8523 had a ratio of about 84:16 with an intrinsic viscosity of about 2.39 dL / g, a melt onset around 133 °C, and a peak melt near 148 °C. PURASORB™ PLG 8218 had a ratio of about 81:19 with an intrinsic viscosity of about 1.83 dL / g, a melt onset near 130 °C,and a peak melt around 144 °C. PURASORB™ PLG 8531 had a ratio of about 84:16 with an intrinsic viscosity of about 3.19 dL / g, a melt onset near 127 °C, and a peak melt around 149 °C.

[0102] The Corbion-supplied PLGAs performed better than the Alpha PLGA. They formed a sphere without crumbling and allowed a screw to be inserted, a favorable indicator of final product performance. However, they also required higher heating temperatures for desired handling. For example, attempts to melt PURASORB™ PLG 8523 started at 130 °C but required incremental increases (up to 160 °C with sustained heating periods) before completely melting and thoroughly mixing. While subsequently handling sterilized samples, PURASORB™ PLG 8218 was satisfactory only after additional microwave heating following an initial heating to 97 °C — though it then became too hot for clinical handling. With PURASORB™ PLG 8523, brief microwave exposure melted the material, but it remained crumbly until the temperature was allowed to drop to about 110 °C, at which point the composite handled well.

[0103] Lower heating temperatures were needed for acceptable handling. One approach was to lower the inherent viscosity of the 85:15 PLGA formulation or to modify the composition by reducing the proportion of PLGA and increasing either the bone content or the plasticizer, since polyethylene glycol has a lower melting and glass-transition temperature and is an effective lubricant.

[0104] Alternatively, Evonik Resomer LG 824S, offered by Evonik demonstrated a lower effective melting point, with complete melting achieved at about 145°C during mixing, and is anticipated to enable heating and molding at post-sterilization temperatures in the range of 100-110°C. This polymer was expected to melt at a significantly lower temperature than both the Alpha and Corbion PLGAs because its amorphous structure provides a lower glass transition temperature of about 32 °C. Therefore, the polymer should only require heating to about 50 °C to become moldable. Moreover, the intrinsic viscosity of the alternative polymer was within the target range. Its degradation profile projected a resorption period of about 6 to 12 months.

[0105] Additional experiments were completed with the Evonik polymer to evaluate its performance in formulations containing about 50 wt.% bone (using various particle sizes) and varying proportions of Evonik Resomer LG 824S and PEG 8000. The objective was to achieve the desired handling characteristics with a lower heating temperature.

[0106] In the processing regime, the polymer and plasticizer components are heated in a torque rheometer under controlled conditions to reduce viscosity and achieve a homogeneous melt.Minor incremental increases in the mixing temperature were used to ensure that the Evonik-sourced PLGA and the PEG fully melted and blended with the bone particles. Adjustments to the formulation — specifically lowering the allograft content, as exemplified in Formulations F and G — further improved the handling properties of the composite, resulting in a material that is both moldable upon heating and capable of setting into a rigid, resorbable implant upon cooling.

[0107] The complete processing cycle for these formulations includes cleaning, weighing of components, mixing at the target temperature, final packaging, and terminal sterilization by gamma irradiation in a range of 25-35 kGy. This cycle yields a homogeneous composite material with improved mechanical stability and optimal bone content by weight, thereby enhancing the efficacy and handling characteristics of the implant for use in bone defect treatments.

[0108] Modifications to embodiments of the present disclosure described in the foregoing are possible without departing from the scope of the present disclosure as defined by the accompanying claims. Expressions such as “including”, “comprising”, “incorporating”, “have”, “is” used to describe and claim the present disclosure are intended to be construed in a non-exclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural.

[0109] The terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting of the disclosure. As used herein, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and / or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0110] It is understood that the present subject matter may be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this subject matter will be thorough and complete and will convey the disclosure to those skilled in the art. Indeed, the subject matter is intended to cover alternatives, modifications, and equivalents of these embodiments, which are included within the scope and spirit of the subject matter of the present disclosure. Furthermore, in the detailed description of the present subject matter, numerous specific details are set forth in order to provide a thorough understanding of the present subject matter. However, it will beclear to those of ordinary skill in the art that the present subj ect matter may be practiced without such specific details.

Claims

CLAIMSWhat is claimed is:

1. A composite, comprising:(a) between about 35 wt.% to about 50 wt.% of a bone component;(b) between about 10 wt.% to 30 wt.% plasticizer comprising polyethylene glycol; and (c) between about 30 wt.% to about 40 wt.% polymer comprising poly(dl-lactide-co- glycolide) having a ratio of lactide to glycolide of between about 75:25 and about 85:15;wherein the composite becomes moldable upon heating to between about the glass transition temperature and about the melting point of the polymer and, upon cooling, sets into a rigid, resorbable implant.

2. The composite of claim 1, wherein the bone component is allograft or xenograft bone.

3. The composite of claim 1 or 2, wherein the bone component comprises cortical and / or cancellous bone tissue.

4. The composite of any one of claims 1 to 3, wherein the polyethylene glycol is polyethylene glycol 8000 (PEG 8000).

5. The composite of any one of claims 1 to 4, wherein the composite is heated to between about 70 °C and about 130 °C.

6. The composite of any one of claims 1 to 5, wherein the composite is heated between about 2 minutes and about 15 minutes or until the composite reaches a uniform temperature before surgical implantation.

7. A composite, comprising:(a) between about 35 wt.% to about 50 wt.% of a bone component;(b) a viscosity-controlling means configured to reduce viscosity of the composite when heated; and(c) a melt temperature controlling means configured to transition the composite to a moldable state when heated between about the glass transition temperature and about the melting point, and to transition the composite to a rigid, resorbable state upon cooling.

8. The composite of claim 7, wherein the bone component is allograft or xenograft bone.

9. The composite of claim 7 or 8, wherein the bone component comprises cortical and / or cancellous bone tissue.

10. A method for treating a bone defect in a patient in need thereof, comprising:(a) heating a composite of any one of claims 1 to 9 to a temperature between about 70 and about 130 °C for between about 2 minutes and about 15 minutes or until the composite is uniformly heated;(b) molding the heated composite to conform to the bone defect; and(c) cooling the molded composite to a temperature below the glass transition temperature, thereby causing the composite to set into a rigid, resorbable implant.

11. The method of claim 10, wherein the bone defect is a bone void.

12. The method of claim 10 or 11, further comprising the step of shaping the heated composite to fill the bone void..

13. The method of any one of claims 10 to 12, wherein the cooling step is performed by applying a cold lavage fluid to rapidly lower the composite’s temperature, or by cooling at room temperature.

14. A heater configured to provide a target heat load for heating the composite of any one of claims 1 to 9 to between about the glass transition temperature and about the melting point of the polymer.

15. The heater of claim 14, comprising a direct-contact heating element.

16. The heater of claim 15, further comprising a housing adapted to receive the composite, a tray configured to be slid into the housing, and one or more direct-contact heating elements arranged to transfer heat by conduction to the composite.

17. The heater of claim 14, wherein the heater comprises an integrated heating element.

18. The heater of claim 17, comprising a reservoir for containing the composite, a plunger operable to extrude the heated composite through an outlet port, and integrated heating elements disposed on the reservoir walls to maintain the composite at the target temperature.

19. The heater of claim 14, comprising dual barrels and corresponding plungers configured to simultaneously dispense heated portions of the composite for mixing or joint delivery to a bone defect.

20. The heater of claim 14, further comprising a chemical heat source positioned adjacent to a composite unit and configured to produce an exothermic reaction upon exposure to air, thereby generating the target heat load required to heat the composite.

21. The heater of any one of claims 14 to 20 configured as a single-procedure-use device for receiving the composite of any one of claims 1 to 9 and supporting sterile and convenient handling of the composite once heated22. An intraoperative kit comprising the composite of any one of claims 1 to 9, the heater of any one of claims 14 to 21, and instructions for use.

23. The method of any one of claims 10 to 13, wherein the heating is effected by employing a heater of any claims 14 to 21 integrated into an intraoperative kit of claim 22.

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